Guest GraemeR Posted September 9, 2006 Share Posted September 9, 2006 Hi all Right, owned my first tt supra auto for about 3 weeks now it has Apexi air filter, full decat and pre-cat with restrictor ring and a Fuel cut defencer, and I have noticed that when I apply my right foot to the floor, I get a little bit of boost(about 0.1-0.2 bar) from around 3000 rpm onwards til about 4000, then it rises to around 0.7 bar and takes off. Checked all the usual stuff like split hoses, nothing found so far. So I decided to try TTC, to see if this would make a difference, still the same, did notice a rocker switch at bottom of dash, thought this might have been a switch for electronic TTC, tried switching this and still the same. Changed boost gauge to see if this was reading wrong, but definatly only 0.7 bar of boost max and around 0.1-0.2 bar from 3000-4000 rpm. Does any1 have any suggestions as to what might be causing the lack of boost until around the 4000 rpm mark. Thanks in advance for any help. Graeme Link to comment Share on other sites More sharing options...
ardasaliah Posted September 9, 2006 Share Posted September 9, 2006 You should be making around 0.6bar of boost from turbo 1 at 2000RMP-up to 4000rpm when the second comes in and both produce 0.8bar if its running in sequencial (sp) Stock. If yours is running in seq then turbo 1 may be dead. Can you hear a turbo whistle from around 1.5000rpm.?? you shoud be able to OR it sounds like it make be stuck in TTC mode if the switch is stuffed. If that the case- then what you described would occur if stock---- But if this is the case then with your mods u should see more then 0.7 bar. Link to comment Share on other sites More sharing options...
Steviekid Posted September 9, 2006 Share Posted September 9, 2006 I think this sounds much more like a boost leak. Depending on your restrictor ring you should probably be getting 1.1-1.2bar when both turbos are online. What I would do first is run the car in mechanical TTC by wiring the IAGC and EGCVs open like the bottom half of this page. Using a foot pump to open the corresponding actuators makes this much easier to do. Also block off the pressure feed to the pressure tank. This will effectively rule out the entire sequential system as the problem. If you still only get 0.7bar you're looking at a boost leak or a duff turbo. I eventually sourced my leak (I was getting 0.7bar with full decat) to a sticking BOV. Link to comment Share on other sites More sharing options...
ardasaliah Posted September 10, 2006 Share Posted September 10, 2006 I think this sounds much more like a boost leak. Depending on your restrictor ring you should probably be getting 1.1-1.2bar when both turbos are online. What I would do first is run the car in mechanical TTC by wiring the IAGC and EGCVs open like the bottom half of this page. Using a foot pump to open the corresponding actuators makes this much easier to do. Also block off the pressure feed to the pressure tank. This will effectively rule out the entire sequential system as the problem. If you still only get 0.7bar you're looking at a boost leak or a duff turbo. I eventually sourced my leak (I was getting 0.7bar with full decat) to a sticking BOV. Possible- But that would be a leak of around 0.5 bar between the 2000 4000 rpm which would be very very obvious!. it would be hissing like mad at 2000 rpm. of course I hope i am wrong and it is a boost leak but I would be more worried about tubby 1 compressor fins I think he did try TTC and it porduced only 0.7bar which is low with the listed mods _Any other ideas to why this problem is occuring to help this guy out. Only had it 3 weeks Link to comment Share on other sites More sharing options...
Kranz Posted September 11, 2006 Share Posted September 11, 2006 A leaking BOV that is still set up to recirculate is actually very quiet. I didn't notice mine until I fitted the twin filter setup and it was venting to atmosphere... continuously! Link to comment Share on other sites More sharing options...
Guest GraemeR Posted September 11, 2006 Share Posted September 11, 2006 Cheers for all the suggestions guys, will give them a try. Graeme Link to comment Share on other sites More sharing options...
Guest GraemeR Posted September 13, 2006 Share Posted September 13, 2006 Once again cheers for the help guys. Had the car to my mates garage 2day, he replaced a load of hoses and also cleaned throttle body and all pipework internally. I now get a build up of boost to 0.5 bar up2 around 3500rpm then at around 4000 rpm boost goes up2 0.8 bar and the car takes off. Any more ideas as to why I should only be making 0.5 bar off 1st turbo. Link to comment Share on other sites More sharing options...
ardasaliah Posted September 13, 2006 Share Posted September 13, 2006 Sounds normal. O.5bar is fine. You can up it with a manual boost controller. Cost about £15. A slight adjustment see 0.7bar on 1st and 0.9 together Link to comment Share on other sites More sharing options...
Guest GraemeR Posted September 13, 2006 Share Posted September 13, 2006 Cheers, don't mean to seem stupid, but where abouts would I need to plumb in to fit a manual boost controller. Link to comment Share on other sites More sharing options...
Steviekid Posted September 14, 2006 Share Posted September 14, 2006 Cheers, don't mean to seem stupid, but where abouts would I need to plumb in to fit a manual boost controller. It goes between the boost source and the wastegate actuator. Block the other pipe from the actuator that goes to the VSV. Link to comment Share on other sites More sharing options...
Guest GraemeR Posted September 14, 2006 Share Posted September 14, 2006 Cheers for that:thumbs: Link to comment Share on other sites More sharing options...
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